<script>
  var xhr = new XMLHttpRequest();
  xhr.onreadystatechange = function() {
    if (xhr.readyState === XMLHttpRequest.DONE) {
      var data = xhr.responseXML;
      var booklist = data.getElementsByTagName('booklist')[0];
      console.log(booklist.childNodes);
      var book = booklist.children[0];
      console.log(book.children[0].innerHTML);               // 方式1
      console.log(book.children[0].firstChild);              // 方式2（会加上引号）
      console.log(book.children[0].firstChild.wholeText);    // 方式3
    }
  };
  xhr.open('GET', 'xml.php');
  xhr.send();
</script>
<p>
  <a href="file:///C:/Users/rise/Desktop/%E9%A6%96%E9%A1%B5/default/10.html">返回</a>
</p>